Crystal Growth & Design最新文献

An overview of some selective research into the solution-phase crystallization and polymorphic behavior of the organic compound, p-aminobenzoic acid (PABA), a representative model compound for a small-molecule pharmaceutical, is presented. The review highlights and interlinks the crystal science underpinning its molecular properties, crystallographic structures, intermolecular crystal chemistry, solution structuring properties, crystallizability, nucleation and growth kinetics and mechanisms, polymorph selection and solvent-mediated morphology, and surface chemistry using both computational modeling and experimental studies. The review mostly focuses on studies of the formation of the α-polymorphic form and how solvent selection and additive action can mediate the crystallization and polymorphic direction process. Additionally, an overview is provided into the crystallographic structures of the four polymorphic forms of PABA and their similarities in terms of both their molecular structure and intermolecular packing. The potential for transferring the fundamental understanding of PABA crystallization to address larger-scale crystallization processes and their control through integrating crystal morphology control is also highlighted.

Solution-phase crystallization of p-aminobenzoic acid highlighting the crystal science underpinning its molecular structure, intermolecular properties, crystal chemistry, solution structure, nucleation, growth, polymorph selection, morphology, and surface chemistry is presented using both computational modeling and experimental studies.

Efficient solvent selection is essential for controlling crystalline solvate formation in pharmaceutical crystallization. A novel COSMO-RS+ML hybrid virtual solvent screening model has been developed to predict solvate propensity by integrating COSMO-RS amorphous-phase miscibility calculations with machine learning predictions of crystallinity contributions. Validated against ten reported studies involving prolific solvate-forming molecules, the model significantly outperformed the pure COSMO-RS method in ranking solvents by their likelihood of forming solvates. When combined with targeted experimental follow-up, this computational approach provides a powerful strategy to accelerate and derisk solvent selection in pharmaceutical crystallization development.

Two ditopic and one tetratopic dialkylamidinium-containing compounds were synthesized and their ability to form hydrogen-bonded networks or frameworks with polycarboxylate anions was studied. A series of 11 different networks were crystallized: in all cases, the dialkylamidinium group is in the E/Z conformation, which rules out the possibility of forming strong paired R₂²(8) hydrogen bonding interactions. Nevertheless, a series of interesting networks were formed, several of which contain solvent-filled channels. It was found that many networks showed a tendency toward solvatomorphism with four forms of one network and three of another isolated under slightly different crystallization conditions. Interestingly, several networks contain partially protonated polycarboxylate anions, which form short antielectrostatic O–H···O^– hydrogen bonds between anions that direct network formation.

The shaping of MOFs is a great challenge toward their use in plenty of applications. Herein we report the in situ spherical shaping of ZIF-7-III and ZIF-9-III triggered by the presence of water and a high excess of the benzimidazolate (bIm) ligand. Starting from different precursors (nitrates or sulfates) and after a mild heating hydrothermal synthesis, spheres of ZIF-7-III and ZIF-9-III were isolated after filtration. Their size varies between 10 and 30 μm by granulometry, and it remains quite homogeneous for the entire population. The spherical shape remains after calcination in order to prepare cathode materials of the LiCoO₂ (LCO) type using ZIF-9-III as the precursor.

Rare-earth metal–organic frameworks (RE-MOFs) have garnered significant attention in materials chemistry owing to their structural diversity and programmable functionality. The judicious selection of organic ligands plays a vital role in constructing novel RE-MOF architectures. JLU-MOF207 was constructed by using [Y₄(μ₃-O)₂(HCOO)₂] secondary building units (SBUs) with a methanetetrakis(p-biphenylcarboxylate) (H₄MTBC) ligand and possessed an unprecedented (4, 4, 12) connected topology. Notably, the interweaving of helical Y–O chains and H₄MTBC ligands within JLU-MOF207 generates ultramicroporous channels (∼ 5 Å diameter), which are decorated with exposed yttrium sites and oxygen-rich environments. JLU-MOF207 exhibits excellent acid, base, solvent, and thermal stability. Due to its confined spaces, multiple open yttrium sites, and oxygen donors in the helical ultramicroporous channels, JLU-MOF207 displays pronounced C₃H₆/C₂H₄ separation selectivity (9.6 at 298 K) and excellent production of 2-benzylidenemalononitrile with 99% yield from benzaldehyde and malononitrile at ambient temperature. The recorded turnover number (TON = 660) and turnover frequency (TOF = 5.5 min^–1) surpass those of most reported MOF-based catalysts for Knoevenagel condensation. This study demonstrates that rational ligand design enables the construction of Y-MOF with dual functionality, providing new perspectives for developing multifunctional porous materials in gas separation and heterogeneous catalysis applications.

We demonstrate for the first time the planar coalescence of high-quality GaP over SiO₂ gratings via an entirely molecular beam epitaxy approach. This establishes a strong foundation for a GaP-on-insulator nanophotonics platform that can be coherently grown on Si and is compatible with visible and near-infrared quantum information processing. A two-stage approach combining periodic supply epitaxy for selective-area lateral epitaxial overgrowth with planar coalescence, originally developed in the GaAs system, was utilized to seamlessly encapsulate dielectric structures aligned to [010] in GaP and restore the planar (100) epitaxial surface. GaP was shown to have improved deposition selectivity and greater temperature compatibility as compared to its arsenide counterpart, as well as a superior growth morphology on par with vapor-phase epitaxy coalescence demonstrations. Further, by orienting the SiO₂ gratings along the [011] direction, high-aspect-ratio voids can be embedded underneath a restored planar surface in a single regrowth step. The ability to seamlessly incorporate noncrystalline materials and laterally structure GaP without the need for damaging processes such as etching unlocks an all-epitaxial GaP-on-insulator platform for nanophotonic and quantum applications.

In recent years, copper-based halides have attracted considerable attention due to their exceptional optical properties. Nevertheless, these materials often exhibit poor thermal stability at elevated temperatures, which significantly limits their potential for practical applications. In this study, we successfully synthesized large-sized, one-dimensional chain-structured Cs₅Cu₃Cl₄Br₂I₂ single crystals using the vertical Bridgman method. The crystal’s structure and composition were characterized through XRD and TG-DTA. Our experimental investigations into the optical properties of the Cs₅Cu₃Cl₄Br₂I₂ single crystals revealed strong cyan emission with a high photoluminescence quantum yield (PLQY) of approximately 90.78% and a significant Stokes shift, attributable to self-trapped exciton (STE) emission. Additionally, we measured the temperature-dependent fluorescence spectra to further elucidate the luminescence mechanism. Notably, the fluorescence intensity of the Cs₅Cu₃Cl₄Br₂I₂ single crystal increased with temperature, peaking at 425 K, a phenomenon seldom observed in copper-based halides. This study underscores the potential of Cs₅Cu₃Cl₄Br₂I₂ single crystals for high-temperature optoelectronic applications.

Metal–organic cages (MOCs), with their unique cavity structures, abundant specific surface areas, and host–guest recognition capabilities, have been consistently demonstrated as catalysts that can significantly accelerate reaction rates and enhance substrate enrichment. Notably, although research has been devoted to the application of MOC in catalysis, studies focusing on the utilization of peroxymonosulfate (PMS) activation for pollutant degradation remain relatively limited. Herein, this study presented the synthesis of a novel cobalt-based metal–organic cage, {Co₄(μ₄-OCH₃)(TBSC)}₂L₄·2DMF·CH₃OH (L = 1,3-adamantanedicarboxylic acid), Ada-MOC, and evaluate its catalytic performance in PMS activation for methylene blue (MB) degradation. The results indicated that the Ada-MOC/PMS system showed a superior MB degradation efficiency of 99.9% within 30 min, with a k_app value 33 times higher than that of the PMS system. Furthermore, the Ada-MOC exhibited high stability and catalytic activity across a broad pH range and under diverse water quality conditions. Mechanistic studies revealed that nonradical pathways such as singlet oxygen (¹O₂) played a dominant role in the reaction process. Based on LC-TOF-MS analysis combined with DFT calculations, three potential degradation pathways for MB have been proposed. The Ada-MOC/PMS system developed in this research demonstrates considerable potential for practical application in organic wastewater remediation.

Molecular manganese halide A₂MnX₄ crystals hold immense potential in optoelectronic applications, making their development highly significant. In this work, we successfully synthesized a novel halide material (IQ)₂MnBr₄ (IQ = Isoquinoline). Its room-temperature photoluminescence was observed, and two distinct phase transitions at critical temperatures of 246.4 and 275.5 K were identified. Moreover, we obtained three crystal structures at different temperatures before and after the phase transition, and revealed the existence of ferroelectricity and ferromagnetism at a particular temperature. Remarkably, experimental data reveal a significant photoluminescence intensity anomaly near the phase transition temperature. This phenomenon originates from tetrahedral distortion induced by structural phase transitions, which alters the distances between cations and Br^– ions, thereby affecting electronic transitions. To verify this conclusion, DFT calculations elucidated the photoluminescence mechanism of this crystal, proving the internal cause behind the influence of distortion on PL intensity in the experimental portion. Finally, we innovatively constructed an optical encryption anticounterfeiting system with time-dependent programming functionality, achieving multilevel security protection for dynamic information. These findings not only provide new theoretical insights into the luminescence regulation mechanisms of halide multiferroic materials but also expand their application prospects in smart optoelectronic devices and advanced anticounterfeiting technologies.

Metal atoms in energetic Metal–Organic Complexes (EMOCs) readily coordinate with solvent molecules, leading to low density and poor thermal stability, which restrict their applications. Herein, we report an N-rich solvent-free EMOC [Cu(HTTA)₂]_n (2) (H₂TTA, 3-(1H-tetrazol-5-yl)-1H-1,2,4-triazol-5-amine) obtained via a single-crystal-to-single-crystal (SCSC) transformation. In this process, precursor H₃TTA·NO₃·H₂O (1) (5-amino-3-(1H-tetrazol-5-yl)-4H-1,2,4-triazol-1-ium nitrate hydrate) coordinates with Cu²⁺ ions, releasing nitrate and water, and the resulting monomers assemble through hydrogen and coodination bonding into a dense three-dimensional framework. [Cu(HTTA)₂]_n shows remarkable thermal stability (T_d = 354 °C, E_k = 250.2 kJ mol^–1) and insensitivity to mechanical stimuli (IS > 40 J, FS > 360 N). Moreover, it promotes the thermal decomposition of ammonium perchlorate (AP), indicating potential as a combustion additive. These results highlight the application prospects of [Cu(HTTA)₂]_n in heat-resistant explosives and green propellants, while also providing new insights into the design of solvent-free EMOCs via SCSC transformation.